89 lines
3.2 KiB
Python
89 lines
3.2 KiB
Python
# Copyright (c) 2010 OpenStack Foundation
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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Scheduler base class that all Schedulers should inherit from
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"""
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import abc
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from oslo_log import log as logging
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from oslo_utils import importutils
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import six
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from stevedore import driver
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import nova.conf
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from nova.i18n import _, _LW
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from nova import objects
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from nova import servicegroup
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CONF = nova.conf.CONF
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LOG = logging.getLogger(__name__)
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@six.add_metaclass(abc.ABCMeta)
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class Scheduler(object):
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"""The base class that all Scheduler classes should inherit from."""
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def __init__(self):
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try:
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self.host_manager = driver.DriverManager(
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"nova.scheduler.host_manager",
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CONF.scheduler_host_manager,
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invoke_on_load=True).driver
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# TODO(Yingxin): Change to catch stevedore.exceptions.NoMatches
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# after stevedore v1.9.0
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except RuntimeError:
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# NOTE(Yingxin): Loading full class path is deprecated and
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# should be removed in the N release.
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try:
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self.host_manager = importutils.import_object(
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CONF.scheduler_host_manager)
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LOG.warning(_LW("DEPRECATED: scheduler_host_manager uses "
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"classloader to load %(path)s. This legacy "
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"loading style will be removed in the "
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"N release."),
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{'path': CONF.scheduler_host_manager})
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except (ImportError, ValueError):
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raise RuntimeError(
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_("Cannot load host manager from configuration "
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"scheduler_host_manager = %(conf)s."),
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{'conf': CONF.scheduler_host_manager})
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self.servicegroup_api = servicegroup.API()
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def run_periodic_tasks(self, context):
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"""Manager calls this so drivers can perform periodic tasks."""
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pass
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def hosts_up(self, context, topic):
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"""Return the list of hosts that have a running service for topic."""
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services = objects.ServiceList.get_by_topic(context, topic)
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return [service.host
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for service in services
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if self.servicegroup_api.service_is_up(service)]
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@abc.abstractmethod
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def select_destinations(self, context, spec_obj):
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"""Must override select_destinations method.
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:return: A list of dicts with 'host', 'nodename' and 'limits' as keys
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that satisfies the request_spec and filter_properties.
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"""
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return []
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